DM74LS26N Equivalent & Substitute Parts

Part Overview

The DM74LS26N is a NAND Gate IC with 4 channels and 2 inputs per channel, manufactured by onsemi in a 14-MDIP package. This component features open collector output configuration and operates within the 4.75V to 5.25V supply voltage range. The part is classified as obsolete, making equivalent and substitute parts necessary for ongoing system maintenance and new design implementations where legacy compatibility is required.

Substiute Parts

DM74LS26N

onsemiIn Stock: 1467DM74LS26N Datasheet

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SN74LS266N

Texas InstrumentsIn Stock: 2089SN74LS266N Datasheet

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SN74LS26N

MotorolaIn Stock: 9598SN74LS26N Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution for the DM74LS26N is determined by the following critical parameters:

• Logic Function: NAND Gate operation with 4 channels and 2 inputs per channel
• Output Configuration: Open Collector topology
• Electrical Specifications: Supply voltage 4.75V ~ 5.25V, output current 8mA maximum, input logic levels 0.8V (low) and 2V (high)
• Package Compatibility: 14-DIP through-hole mounting with 0.300" (7.62mm) pitch
• Series Classification: 74LS logic family

Substitute parts must maintain identical logic function, output configuration, electrical operating parameters, and physical package dimensions. The SN74LS26N (Motorola) qualifies as a direct equivalent, sharing the same NAND gate logic type and all critical electrical parameters. The SN74LS266N (Texas Instruments) is listed as a functional alternative but operates as an XNOR gate rather than NAND, making it suitable only for applications where the logic function difference is acceptable and the electrical parameters align.

Parameter Comparison

Engineering Selection Recommendations

SN74LS26N (Motorola) is the primary equivalent for direct replacement of the DM74LS26N. Both parts share identical logic function (NAND Gate), electrical specifications, and package configuration. The SN74LS26N demonstrates faster propagation delay (32ns versus 45ns) and lower capacitive load requirements (15pF versus 50pF), providing improved performance margins. However, the part is classified as obsolete, consistent with the original component status.

SN74LS266N (Texas Instruments) is an active product offering superior long-term availability and RoHS3 compliance. This part maintains electrical compatibility and package dimensions but implements XNOR logic rather than NAND logic. Selection of the SN74LS266N requires verification that the application logic can accommodate the functional difference between NAND and XNOR gate operations. The SN74LS266N exhibits faster propagation delay (30ns) and lower quiescent current (13mA maximum), supporting applications with stricter timing or power constraints.

Frequently Asked Questions (FAQ)

Q: Can the SN74LS266N directly replace the DM74LS26N without circuit modification?

A: The SN74LS266N shares identical electrical parameters, supply voltage, output current, input logic levels, operating temperature range, and 14-DIP package configuration. However, the logic function differs: DM74LS26N implements NAND gate logic while SN74LS266N implements XNOR gate logic. Direct substitution is possible only if the application circuit logic can function with XNOR operation in place of NAND operation.

Q: What is the difference between the DM74LS26N and SN74LS26N?

A: Both parts implement identical NAND gate logic with 4 channels and 2 inputs per channel. The primary differences are manufacturer (onsemi versus Motorola) and propagation delay specifications (45ns versus 32ns at 5V with 50pF and 15pF load capacitance respectively). Both parts are obsolete and share the same 14-DIP package configuration and electrical operating parameters.

Q: Why is the SN74LS266N listed as a substitute if it has different logic?

A: The SN74LS266N is included because it maintains all critical electrical parameters (supply voltage, output current, input logic levels, operating temperature) and physical package compatibility (14-DIP through-hole). The logic function difference (XNOR versus NAND) must be evaluated within the specific application context. For applications where logic function substitution is acceptable, the SN74LS266N offers the advantage of active product status and RoHS3 compliance.

Q: Are there any compliance or availability differences between these parts?

A: The DM74LS26N and SN74LS26N are both obsolete with limited future availability. The SN74LS266N is an active product with 2000 pieces in stock, offering superior long-term availability. The SN74LS266N carries RoHS3 compliance certification, while the SN74LS26N (Motorola) is RoHS non-compliant. All three parts are REACH unaffected and classified under ECCN EAR99.

Q: What are the propagation delay implications for substitution?

A: The DM74LS26N specifies 45ns maximum propagation delay at 5V with 50pF load. The SN74LS26N reduces this to 32ns with 15pF load, and the SN74LS266N achieves 30ns with 15pF load. Both substitutes provide faster response times, which is beneficial for timing-critical applications. Applications with tight timing margins may require re-validation with the faster substitute parts.